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NFSSVC(2)		       System Calls Manual		       NFSSVC(2)

NAME
     nfssvc -- NFS services

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <sys/param.h>
     #include <sys/mount.h>
     #include <sys/time.h>
     #include <nfs/rpcv2.h>
     #include <nfsserver/nfs.h>
     #include <unistd.h>

     int
     nfssvc(int flags, void *argstructp);

DESCRIPTION
     The  nfssvc()  system  call  is used by the NFS daemons to pass information
     into and out of the kernel and also to enter the kernel as a server daemon.
     The flags argument consists of several bits that show what action is to  be
     taken  once  in the kernel and the argstructp points to one of three struc-
     tures depending on which bits are set in flags.

     On the client side, nfsiod(8) calls nfssvc() with the flags argument set to
     NFSSVC_BIOD and argstructp set to NULL to enter the kernel as a  block  I/O
     server daemon.  For NQNFS, mount_nfs(8) calls nfssvc() with the NFSSVC_MNTD
     flag,  optionally	or'd with the flags NFSSVC_GOTAUTH and NFSSVC_AUTHINFAIL
     along with a pointer to a

     struct nfsd_cargs {
	     char	     *ncd_dirp;      /* Mount dir path */
	     uid_t	     ncd_authuid;    /* Effective uid */
	     int	     ncd_authtype;   /* Type of authenticator */
	     int	     ncd_authlen;    /* Length of authenticator string */
	     u_char	     *ncd_authstr;   /* Authenticator string */
	     int	     ncd_verflen;    /* and the verifier */
	     u_char	     *ncd_verfstr;
	     NFSKERBKEY_T    ncd_key;	     /* Session key */
     };

     structure.  The initial call has only the NFSSVC_MNTD flag set  to  specify
     service  for  the	mount point.  If the mount point is using Kerberos, then
     the mount_nfs(8) utility will return from nfssvc() with errno ==  ENEEDAUTH
     whenever the client side requires an ``rcmd'' authentication ticket for the
     user.   The  mount_nfs(8)	utility will attempt to get the Kerberos ticket,
     and if successful	will  call  nfssvc()  with  the  flags	NFSSVC_MNTD  and
     NFSSVC_GOTAUTH after filling the ticket into the ncd_authstr field and set-
     ting  the	ncd_authlen and ncd_authtype fields of the nfsd_cargs structure.
     If mount_nfs(8) failed to get the ticket, nfssvc() will be called with  the
     flags  NFSSVC_MNTD, NFSSVC_GOTAUTH and NFSSVC_AUTHINFAIL to denote a failed
     authentication attempt.

     On the server side, nfssvc() is called with  the  flag  NFSSVC_NFSD  and  a
     pointer to a

     struct nfsd_srvargs {
	     struct nfsd     *nsd_nfsd;      /* Pointer to in kernel nfsd struct */
	     uid_t	     nsd_uid;	     /* Effective uid mapped to cred */
	     uint32_t	     nsd_haddr;      /* Ip address of client */
	     struct ucred    nsd_cr;	     /* Cred. uid maps to */
	     int	     nsd_authlen;    /* Length of auth string (ret) */
	     u_char	     *nsd_authstr;   /* Auth string (ret) */
	     int	     nsd_verflen;    /* and the verifier */
	     u_char	     *nsd_verfstr;
	     struct timeval  nsd_timestamp;  /* timestamp from verifier */
	     uint32_t	     nsd_ttl;	     /* credential ttl (sec) */
	     NFSKERBKEY_T    nsd_key;	     /* Session key */
     };

     to  enter	the kernel as an nfsd(8) daemon.  Whenever an nfsd(8) daemon re-
     ceives a Kerberos authentication ticket, it will return from nfssvc()  with
     errno  ==	ENEEDAUTH.  The nfsd(8) utility will attempt to authenticate the
     ticket and generate a set of credentials on the server for the ``user  id''
     specified	in  the field nsd_uid.	This is done by first authenticating the
     Kerberos ticket and then mapping the Kerberos principal to a local name and
     getting a set of credentials for that user  via  getpwnam(3)  and	getgrou-
     plist(3).	 If  successful, the nfsd(8) utility will call nfssvc() with the
     NFSSVC_NFSD and NFSSVC_AUTHIN flags set to pass the credential  mapping  in
     nsd_cr  into  the kernel to be cached on the server socket for that client.
     If the  authentication  failed,  nfsd(8)  calls  nfssvc()	with  the  flags
     NFSSVC_NFSD and NFSSVC_AUTHINFAIL to denote an authentication failure.

     The   master   nfsd(8)   server   daemon	calls  nfssvc()  with  the  flag
     NFSSVC_ADDSOCK and a pointer to a

     struct nfsd_args {
	     int     sock;   /* Socket to serve */
	     caddr_t name;   /* Client address for connection based sockets */
	     int     namelen;/* Length of name */
     };

     to pass a server side NFS socket into  the  kernel  for  servicing  by  the
     nfsd(8) daemons.

RETURN VALUES
     Normally nfssvc() does not return unless the server is terminated by a sig-
     nal  when	a  value  of  0  is returned.  Otherwise, -1 is returned and the
     global variable errno is set to specify the error.

ERRORS
     [ENEEDAUTH]	This special error value is really used for  authentica-
			tion support, particularly Kerberos, as explained above.

     [EPERM]		The caller is not the super-user.

SEE ALSO
     mount_nfs(8), nfsd(8), nfsiod(8)

HISTORY
     The nfssvc() system call first appeared in 4.4BSD.

BUGS
     The  nfssvc() system call is designed specifically for the NFS support dae-
     mons and as such is specific to their requirements.  It should  really  re-
     turn  values  to  indicate  the  need  for  authentication  support,  since
     ENEEDAUTH is not really an error.	Several fields of  the	argument  struc-
     tures are assumed to be valid and sometimes to be unchanged from a previous
     call, such that nfssvc() must be used with extreme care.

FreeBSD ports 15.quarterly	  June 9, 1993			       NFSSVC(2)

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